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Scalable volume groups first appeared in AIX 5.3. They allow
a maximum of 1024 physical volumes and 4096 logical volumes per volume group.
This is pretty cool for large systems. In the ‘old days’ we could end up in
situations where we’d reached the maximum PV count (32 or 128) for a VG and
have to create a new VG to work around the issue. I use scalable VGs for all my new large AIX system builds. The following command will create a scalable VG (named svg ) on hdisk4. You’ll notice that MAX
PVs is set to 1024 and MAX LVs is set to 256.... [More]

Following on
from my previous post, on working with scalable VGs. https://www.ibm.com/developerworks/mydeveloperworks/blogs/cgaix/entry/working_with_aix_scalable_volume_groups1?lang=en You may find
yourself in a situation where you’d like to convert a VG to scalable. For example,
you might start off with a normal VG i.e. one that can support a maximum of 256
LVs and 32 PVs. # mkvg -s
512M -y myvg hdisk5 myvg # lsvg myvg VOLUME
GROUP: myvg VG IDENTIFIER: 00f6027300004c0000000133aa24d1f6 VG
STATE:... [More]

I was contacted recently by a customer who was attempting to restore an AIX 5.3 Versioned WPAR (VWPAR) from backup using NIM. The restore worked OK but the data was restored to the wrong volume group! When the VWPAR was created, the –g option was specified with mkwpar to force the creation of the VWPAR file systems in a separate volume group (named wparvg) rather than the default location of the Global root volume group (rootvg). # mkwpar - g wparvg -n p8vw2 -B /cg/53gibbo.mksysb -C -O Running lsvg against... [More]

AIX has a new “critical volume group” capability which will monitor for the loss or failure of a volume group. You can apply this to any volume group, including rootvg. If applied to rootvg, then you can monitor for the loss of the root volume group. This feature may be useful if your AIX LPAR experiences a loss of SAN connectivity e.g. total loss of access to SAN storage and/or all SAN switches. Typically, when this happens, AIX will continue to run, in memory for a period of time and will not immediately crash. Often you... [More]